feat: 对接生图功能

Co-authored-by: Copilot <copilot@github.com>

server/utils/openai.ts

@@ -1,6 +1,22 @@
 // server/utils/openai.ts
 import OpenAI from "openai";
-import type { BaseOptions } from "#shared/types/openai";
+import type { BaseOptions, IImageGenerateData } from "#shared/types/openai";
+
+const IMAGE_GENERATION_URL = "https://api.qflink.xyz/v1/images/generations";
+const IMAGE_GENERATION_MODEL = "gpt-image-2";
+const IMAGE_GENERATION_SIZE = "1024x1024";
+
+interface IImageGenerationResponse {
+  /** 上游创建时间 */
+  created?: number;
+  /** 上游图片生成结果列表 */
+  data?: Array<{
+    /** 上游返回的修订提示词，可能为空 */
+    revised_prompt?: string;
+    /** 生成图片地址 */
+    url?: string;
+  }>;
+}
 
 /** 通用 AI 调用函数（支持文本 / 图文 / 多模态） */
 export const askAI = async ({
@@ -84,6 +100,38 @@ export const askVision = async (
   return res.output_text;
 };
 
+/** 调用图片生成接口，完整 API Key 只在服务端使用 */
+export const askImg = async ({
+  apiKey,
+  prompt
+}: {
+  apiKey: string;
+  prompt: string;
+}): Promise<IImageGenerateData> => {
+  const result = await $fetch<IImageGenerationResponse>(IMAGE_GENERATION_URL, {
+    method: "POST",
+    headers: {
+      Authorization: `Bearer ${apiKey}`,
+      "Content-Type": "application/json"
+    },
+    body: {
+      model: IMAGE_GENERATION_MODEL,
+      prompt,
+      size: IMAGE_GENERATION_SIZE
+    }
+  });
+
+  const image = result.data?.[0];
+  if (!image?.url) {
+    throw new Error("图片生成失败");
+  }
+
+  return {
+    imageUrl: image.url,
+    revisedPrompt: image.revised_prompt
+  };
+};
+
 /** 调用流式接口 */
 export const askStream = async (
   options: BaseOptions & {